SP9VFD antenna system for EME

2007 antennas SP9VFD antenna system for EME
2007 antennas

EME communications have fascinated Rafał SP9VFD from the very beginning of his amateur radio hobby, ie since 1991, when he received the first license at the age of 15. At the time, his favorite reading was UHF guide  “Poradnik Ultrakrótkofalowca”  by SP6LB. However, it was only in 2007 that he managed to carry out the first EME contact in the 144 MHz band. Using a set of yagi F9FT antennas 4 x 9 el. mounted on the balcony carried out dozens of QSO EME in the band with the emission of JT65B.

May 2019

After many years, Rafał SP9VFD decided to return to the EME and the long weekend of May 2019 was dedicated to the assembly of a unique 8 x 23 el. set. of yagis for the 432 MHz band. Antennas Rafał has been building in the garage for the last two months. They are designed for EME operation, but they can also be used for work by satellites and for receiving telemetry data from the moon’s orbit (recently a very development topic). A single antenna was made based on the DK7ZB study and has a gain of approximately 17 dBd at a length of 560 cm. A set of 8 such antennas should give a theoretical gain of about 26 dBd, but in practice it will be lower due to losses on cables and connectors. Rafał checked each of the antennas individually, the DK7ZB design is repeatable while maintaining precision and diligence.

There is still to make 8 connection cables, a splitter, a relay for splitter, LNA and two independent coaxial cables: 7/8 “for TX and 1/2” for RX. The set of antennas will be powered by 8 port splitter I0JXX (8 N sockets and one main 7/16), which is a proven solution. For transmission and reception, Rafał has TS-2000X (QRO is under preparation) and a parallel SDRplay RSPduo receiver. The first rehearsals will be 50 W.

The antenna rotation construction is placed in the antenna trolley. The AZ drive is a solid old-style Żyrardów rotor from the late 90’s that drives a 60 mm tube in the thrust bearing. At the end of the pipe, an EL rotating mechanism is welded, using a cross beam, two solid steel hinges and an 24 inch electric actuator. The whole structure is made by Rafał himself. The 14 m mast was made over 10 years ago for directional HF antennas. Temporarily to control the rotation, Rafał uses the old SAK232 controller for AZ, and Datcom 500controller  for EL. Ultimately, Rafał wants to perform comprehensive autonomous control based on the Arduino project.

SP9VFD antenna system for EMESP9VFD antenna system for EMESP9VFD antenna system for EMERafał, we are waiting for the completion of the work and the first QSO, we are keeping our fingers crossed, let us know about the progress. We wish you not only successful Earth-Moon-Earth QSOs, but also Earth-Mars-Earth HI HI!

More photos from the antenna system installation are published by Rafał in his Google Drive.

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